1. Field of the Invention
The present invention relates generally to product filling machines for packaging food products and the like. More particularly, the present invention relates to a simplified pneumatic controller for controlling all functions of a linear volumetric pocket filler.
2. Related Art
In the food processing and other similar industries, many products are packaged using mechanical product measuring and dispensing machines. Examples of such machines are shown in U.S. Pat. Nos. 6,041,835 and 6,145,552, for example. Such packaging machines generally comprise a measuring and discharge head which is positioned above a conveying device, such as a conveyor belt. The conveying device moves empty containers past the discharge head, while the discharge head portions and drops the product into each container as it passes by. The containers may move past more than one such machine if multiple products are to be placed therein, and then they typically proceed to an additional machine which places a top seal or cap on the container to seal it. These types of product filling machines help ensure precise portion measurements, and also avoid some of the labor cost, cleanliness, and other drawbacks of hand packaging.
The moving components of a mechanical product measuring and dispensing machine may be powered by pneumatic actuators. In prior machines, the operation and timing of the pneumatic actuators is typically controlled by a complex electronic controller incorporating a microprocessor, multiple power conversion components, an air compressor, various types of transducers, and pneumatic switches and valves, which ultimately control the pneumatic actuators. Through modification of the software, the timing and operation of a variety of electronic, pneumatic, and other components can be very accurately and independently controlled to allow one system to accommodate a variety of products and packaging criteria.
While such a prior art system is very versatile, it is also very complicated and expensive. Many product packaging operations neither need such flexibility, nor justify the expense of such a system. In many operations, a machine incorporating just one or a few of the operating configurations of the microprocessor controlled system is sufficient. Moreover, providing both electrical and compressed air power sources to a single product packaging machine imposes greater facilities requirements on the user.
It has been recognized that it would be advantageous to develop a controller for a volumetric pocket filler that uses only a compressed air source to power its basic functions.
It has also been recognized that it would be advantageous to develop a controller for a volumetric pocket filler that is relatively simple and inexpensive.
The invention advantageously provides a simplified controller for a volumetric pocket filler having a plurality of pneumatically powered components. In one illustrative embodiment, the controller comprises a pneumatically powered actuator, moveable along a motion path, and a plurality of pneumatic switches, disposed along the motion path of the actuator. The pneumatic switches are configured for contact with the actuator, to control air flow to the plurality of pneumatically powered components of the volumetric pocket filler.
In accordance with a more detailed aspect of the present invention, the pneumatically powered actuator comprises a pneumatic cycle control cylinder with a piston rod having an actuator block disposed on its end. The piston rod travels through a linear stroke, from a home position to an extended position. As the piston rod extends from the home position to the extended position, then back again, the actuator block sequentially contacts and then releases the plurality of pneumatic switches.
In accordance with another more detailed aspect of the present invention, the plurality of pneumatic switches are locationally adjustable relative to the motion path of the actuator block, such that the relative timing of operation of their associated components may be adjusted.
In accordance with yet another more detailed aspect of the present invention, the controller includes a one shot cycle control system, for preventing undesired repeated operation of the controller in the event the container conveyor stops.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.